Well, the topic speaks for itself. How much emphasis should I focus on maintenance? I know that this varies with different classes of SCPs, obviously Keter will need extensive maintenance so nothing bad happens, but if it's.. say, Euclid or Safe?

Yes, like any man-made object there are lots of maintenance tasks and inspections that would go with any containment unit realistically. This aspect rarely gets even a mention in most cases. Balance thurough research with brevity as well, maintenance details can bog containment procedures too.